Abstract:
A gas cap for a thermal spray gun has a passage therethrough including an entrance channel, an exit channel, and an intermediate channel connecting between the entrance and exit channels. The entrance channel is cylindrical on an entrance axis, and the exit channel is convergingly conical on an exit axis oriented at 45.degree. to the entrance axis. The intermediate channel is symmetrical to the plane of the entrance and exit axes and has a near portion and a far portion. The near portion is semicylindrical about the entrance axis, and the far portion is semicylindrical about a far axis segment lying in the plane. That segment is offset from the entrance axis away from the exit end of the gas cap, and is oriented at 14.degree. to the entrance axis, the three axes intersecting at a common point.
Abstract:
A method for producing a dense and tenacious coating with a thermal spray gun including a nozzle member and a gas cap. The gas cap extends from the nozzle and has an inwardly facing cylindrical wall defining a combustion chamber with an open end and an opposite end bounded by the nozzle. An annular flow of a combustible mixture is injected at a pressure of at least two bar above atmospheric pressure from the nozzle coaxially into the combustion chamber. An annular outer flow of pressurized air is injected from the nozzle adjacent to the cylindrical wall. Powder particles having a heat-stable, non-fusible component and a heat-softenable component, and entrained in a carrier gas, are fed axially from the nozzle into the combustion chamber. An annular inner flow of pressurized air is injected from the nozzle into the combustion chamber coaxially between the combustible mixture and the powder-carrier gas. Upon combusting the annular mixture a supersonic spray stream containing the powder is propelled through the open end to produce a coating.
Abstract:
An improved combustion head for use with flame spray apparatus constructed according to the principles described in U.S. Pat. No. 4,416,421 is provided with a recess in the floor of the counterbore receiving hot pressurized combustion gases from the combustion chamber. The recess is of depth sufficient to redistribute the heat of the combustion gases to prevent local hot spots in the counterbore and to avoid cracking and erosion in the combustion head by reducing thermal fatigue which occurs in cyclic use of the flame spray apparatus. The improved combustion head is also provided with radially spaced longitudinal channels extending inwardly from the periphery thereof, along which channels cooling water is passed to cool the improved combustion head.
Abstract:
A thermal spray gun includes a first burner for producing a first fan-shaped flame, a second burner for producing a second fan-shaped flame parallel to the first in sufficient proximity to commingle into a combined fan-shaped flame. Powder is dispersed into a fan-shaped powder spray entrained between the first and second flames. The gun body has a fan-shaped powder chamber with an open side opening forwardly from the gun body between the first flame and the second flame and with an apex location opposite the open side. First and second powder ducts each terminate at the apex location with a common axis perpendicular to the fan-shaped chamber such as to mutually impinge the first and second powder streams into a combined powder stream dispersing through the fan-shaped powder chamber into the fan-shaped powder spray. A first fan-shaped air flow is introduced between the first flame and the fan-shaped air flow is introduced between the first flame and the fan-shaped powder spray, and a second fan-shaped air flow is introduced between the second flame and the fan-shaped powder spray.
Abstract:
A spray gun comprises a nozzle defining an elongated, axially extending spray channel, a coaxial inlet leading thereto and having a flow-accelerating contour, and a coaxial combustion chamber leading to the inlet, the combustion chamber having a diameter larger than that of the spray channel. A nozzle head is displaceably mounted in the combustion chamber and is axially adjustable with respect to the inlet, the nozzle head feeding the fusible material into the combustion chamber and carrying a burner nozzle and respective conduits feeding a combustion gas and a spray channel flushing gas into the combustion chamber. An ignition electrode projects into the combustion chamber and is arranged for adjustment with respect to the burner nozzle in a direction transverse to the axis, and a control circuit comprises a switching element for supplying electric current to the ignition electrode whereby a spark is formed between the ignition electrode and the burner nozzle for igniting the combustion gas in the combustion chamber, and respective controllers for feeding the combustion gas and the flushing gas through the respective conduits, the control circuit sequentially operating the controller for feeding the flushing gas, the switching element for supplying electric current to the ignition electrode and the controller for feeding the combustion gas.
Abstract:
Method and apparatus for high temperature heating, melting, refining and superheating of materials, such as steel scrap, metals, ceramics or glass. The invention provides an economizing method of hydrocarbon fluid fuel combustion in an ongoing flame in a liquid cooled combustion chamber by separately supplying streams of fuel and at least two oxidizing gases wherein a first oxidizing gas reacts with the fuel, and a second oxidizing gas is directed about the flame core to further react with the fuel, while controlling the flow of the fuel, the oxidizing gases and cooling liquid to provide the required heat input, combustion product chemistry, temperature, velocity, emissivity and combustion block temperature. Also disclosed are burners for carrying out the invention.
Abstract:
Disclosed is a powder container for a flame spraying torch having an outlet normally closed by an elastomeric plug provided with inner and outer closely spaced diaphragms. The outer diaphragm has an aperture sized for a wiping fit with a powder dispensing tube as the latter approaches and opens a normally closed slit crosswise of the inner diaphragm thereby safeguarding against the loss of powder during both insertion and withdrawal of a powder dispensing tube through the two diaphragms. The powder dispensing tube has an inlet end upstanding axially within a well sized for telescopic assembly about the dispensing end of the powder container.
Abstract:
The invention contemplates an elongate extension nozzle attachment for a gas torch whereby flame-spraying of coating-powder material may be applied with precision to the bore of a workpiece. The attachment is detachably securable to conventional torch and/or gas-distributor structure and provides independent flows of (a) carrier gas and powder and (b) combustible-gas mixture to a nozzle which is removably fitted to the discharge end. Provision is made for optional use of one or more flame-shaping discharges of air, inert gas or the like at the discharge end, using a further independent supply system within the attachment.
Abstract:
The invention contemplates a selectively operative flame-shaping feature in application to a powder-spraying gas torch, whereby directional jets of compressed-air or other pressure fluid may be discharged into angularly spaced off-axis regions of a developing flame spray, with selective rotational adjustment of the angular orientation of jet discharge with respect to the axis of flame-spray discharge.
Abstract:
A metal spray powder blend is provided characterized by the property of forming a dense coating on a metal substrate comprising a self-fluxing nickel-base alloy powder having intimately associated with the surface thereof by blending an aluminum powder ranging in amount from about 0.5 to 5% by weight, the average size ratio of the nickel-base alloy powder to the aluminum powder being over 5:1, the aluminum powder having an average particle size of less than about 15 microns. A preferred method of spraying the powder is to gravity feed it into the flame of a metal spraying torch.